Phenolic Content and Antioxidant Activity of Raspberry and Blackberry Cultivars

ABSTRACT: Raspberry (Aksu Kırmızısı, Rubin, Newburgh, Hollanda Boduru, Heritage) and blackberry (Bursa 1, Bursa 2, Jumbo, Chester) cultivars were assayed for antioxidant activity (determined as 2,2-azino-di-[3-ethylbenzothialozine-sulphonic acid][ABTS], 2,2-diphenyl-1-picrylhydrazyl radical [DPPH], and cupric ion reducing antioxidant capacity [CUPRAC]), total phenol, total flavonoid, and total anthocyanin contents. In addition, 10 anthocyanins and anthocyanidins were determined in raspberry and blackberry by liquid chromatography-mass spectrometry (LC-MS/MS). Raspberry and blackberry had the highest ABTS, DPPH, CUPRAC, total phenol, and total flavonoid contents in methanol extracts, whereas total anthocyanin contents were the highest in water extracts. The antioxidant activity of the raspberry and blackberry was directly related to the total amount of phenolic compounds detected in the raspberry and blackberry. All antioxidant activity values were highly correlated with anthocyanin content in blackberry (0.93 ≤ r ≤ 0.99, P = 0.05). On the other hand, high correlation between total flavonoid content and antioxidant activity was recorded in water extract of blackberry (0.91 ≤ r ≤ 0.93, P = 0.05). ABTS value was highly correlated with total flavonoid content in methanol extract (r = 0.90), whereas total flavonoid content was relatively less correlated with DPPH (r = 0.85) and CUPRAC (r = 0.89).     

The Microstructure,Texture and Mechanical Properties of Friction Stir Welded Aluminum Alloy

Russian Journal of Non-Ferrous Metals - The microstructure and texture of 7075-T6 FSW weld with optimal parameters are investigated using optical microscopy, electron back scatter diffraction and...     

Mixed convection and entropy production of a hybrid nanofluid in a porous cylindrical enclosure with rotating top wall

A numerical study is carried out to investigate heat transfer and entropy production of a hybrid nanofluid in a porous cylindrical enclosure with a rotating top wall. The bottom wall of the cylinder is taken as hot, the sidewall is adiabatic, except the top wall is considered cold and rotates at an angular velocity (ΩR). The effects of a hybrid nanofluid flow on heat transfer and entropy generation are examined for an aspect ratio (H/R = 1). A FORTRAN program was elaborated for solving the governing equations based on the finite volume method. Good agreement was found when comparing results from this study against published data. Our results are presented for different Reynolds number values (100 ≤ Re ≤ 1500), nanoparticle fraction NP (0 ≤ ϕ ≤ 0.08), Darcy number (10⁻⁴ ≤ Da ≤ 10⁻¹) and porosity of the porous medium (0.2 ≤ ε ≤ 0.99) for Ri = 0.5, 1,5 and 8, where (Ri = Gr/Re2). They reveal that the heat transfer increases with Re, ϕ, Da, Ri, and decreasing ε. The simulation data were used to propose four different correlations for $\overline{\mathit{Nu}}$ and S_tot as Re, Da, Ri, ϕ, and ε.     

Comparison of antioxidant capacity of cow and ewe milk kefirs

This research aimed to evaluate the effects of using either grain or commercial starter culture on the antioxidative capacity of cow and ewe milk kefirs. The antioxidant capacity of kefir samples during fermentation and 21 d of storage was assessed by using 3 assays: 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical cation decolorization; 2,2-diphenyl-1-picrylhydrazyl (DPPH^?) radical scavenging activity assay; and Fe⁺³-reducing power (ferric reducing antioxidant power assay, FRAP). Vitamin E and β-carotene contents were also quantified. All kefir samples exhibited varying values for DPPH, ABTS, and FRAP assays depending on the starter culture and milk type. Vitamin E and β-carotene contents were similar in all kefir samples during storage. The results of this study suggest that milk type (cow or ewe) and culture type (kefir grains or commercial starter) were the significant parameters for the antioxidative activity of kefir.     

Effects of process parameters on the synthesis of palladium membranes

In this study, palladium film plating was carried out on porous glass supports using the electroless plating technique. This technique was applied to study the effects of bath temperature and reducing agent concentration on the amount and the structure of palladium plated. Hydrazine concentration was fixed at 10 ml/L in the baths using 1 M hydrazine solution while the temperature was changed between 25 and 50 °C. The total mass gain and Pd/Si ratio (wt/wt%) on the surface were obtained as 7.76 mg/cm² and 68.7 in a bath temperature of 35 °C, respectively. With the help of LM microscope analysis, thickness of the membrane prepared at this temperature was determined as 31 μm. In the studies in which the bath temperature was examined as a parameter, the minimum total mass gain was obtained in a plating bath temperature of 43 °C. In the second part of this study, in order to study the concentration effect of hydrazine, hydrazine concentration was increased to 15 and 20 ml/L at a bath temperature of 43 °C. It was shown that as a result of increasing the hydrazine concentration from 10 ml/L to 15 ml/L, total mass gain increased more than twice and a denser plating was obtained. On the contrary to expectations, a result less successful than in the study of 10 ml/L concentration was obtained through increasing hydrazine concentration to 20 ml/L. This study showed that bath temperature of 25 °C was too low to carry out effectively autocatalytic reaction on the activated surface. Plating bath decomposed in plating studies performed at 43 °C and 50 °C. In the studies where hydrazine concentrations were examined as a parameter, it was observed that the stability of the bath could not be maintained in each of the three baths throughout the plating time. The highest decomposition rate was also predicted for the study carried out at a hydrazine concentration of 20 ml/L. Decomposition seen at high temperatures and high hydrazine concentrations was explained as a consequence of insufficient EDTA concentrations in plating baths.     

Synthesis,antibacterial and antifungal evaluation of thio- or piperazinyl-substituted 1,4-naphthoquinone derivatives

A series of S-, S,S-, S,O-, N- and N,S-derivatives from 2,3-dichloro-1,4-naphthoquinone compound 1 were synthesized in different reaction media and evaluated for their antibacterial and antifungal activities. The structures of the novel products were characterized by spectroscopic methods, such as microanalysis, ¹H NMR, ¹³C NMR and MS. Among the tested compounds 9, 12 and 18 are the most effective compounds against Candida tenuis as potent antifungal compounds. Compound 9 is also the most effective compound against Staphylococcus aureus as a potent antifungal compound.